1. Field of the Invention
The present invention generally relates to an obstacle recognition apparatus and method, and more particularly to an obstacle recognition apparatus, obstacle recognition method and an obstacle recognition program, applied in a mobile robot apparatus to recognize an obstacle on a floor, and a mobile robot apparatus.
This application claims the priority of the Japanese Patent Application No. 2002-073388 filed on Mar. 15, 2002, the entirety of which is incorporated by reference herein.
2. Description of the Related Art
Needless to say, it is important for the autonomous robot to be able to recognize its surroundings for programming a route it should take and move along the route. The conventional mobile or locomotive robots include a wheeled type robot, walking type robot (bipedal and quadrupedal), etc. The wheeled type robot provided around it ultrasonic sensors disposed in parallel to the floor surface to detect reflected ultrasound from a wall or the like. Since the ultrasonic sensors are disposed in parallel to the floor surface, they will not detect such return ultrasound from the floor surface and can thus recognize all points having reflected the ultrasound as obstacles. Therefore, it is easy to process the ultrasound information for recognition of such obstacles. Since this method permits to detect only an obstacle having a predetermined height, however, the robot cannot recognize any obstacle such as a small step (lower than the predetermined height) or a hole or concavity in the floor. On the other hand, the walking robot, quadrupedal or bipedal, has such a distance sensor installed on a part thereof that can actively be changed in posture, such as the head, hand end, etc.
The quadrupedal walking robot (entertainment robot) having recently been well known employs a distance sensor installed on the head thereof to derive floor parameter from a posture of the robot and judge, on the basis of the floor surface parameter, whether a ranged point is a floor surface or an obstacle.
However, the method adopted in the quadrupedal walking robot can range only one point (or several points when the distance detection is repeatedly tried with the robot posture being changed) and so can hardly detect the surroundings of the robot satisfactorily. Also, this method can detect one point at each time of distance detection, it is not so highly reliable in terms of the accuracy of distance detection.